A common business practice is to provide a second self-addressed envelope within a first envelope sent to the addressee. However, providing the second envelope is an additional expense that is paid by the sender or passed on to the customer in the form of higher prices. Additional expense is incurred as clerical personnel are required to stuff the second envelope within the first envelope mailed to the address. Once the first envelope is opened, it becomes a waste item which is thrown away. Additional expense is also generated when the second self-addressed envelope is not provided, since the receiver must provide a separate return envelope.
To eliminate the need for a separate forwarding envelope and a separate return envelope for each original addressee, a remailable envelope has been described, which serve both the forwarding and the return function. One example of such an envelope is described in U.S. Pat. No. 3,558,040 to Krueger on Jan. 26, 1971. Another example of such an envelope is described in U.S. Pat. No. 4,308,987 to Solomon on Jan. 5, 1982. These two-way envelopes use a sealing flap carried by the front panel to seal on the back panel for a first use, and a resealing flap carried by the back panel of the forwarding envelope which folds over the top of the original envelope to seal on the front panel. The front panel, therefore, becomes obstructed and/or marred when the envelope is sealed and/or opened for the re-use. In addition, these two-way envelopes often require tedious manipulation by the original addressee to prepare the envelope and insertion for remailing resulting in misuse or damage to the return envelope.
However, such envelopes may also result in loosening of sealing strips, glue patches or loose edges being left on the envelope which interferes with machine sorting equipment on the return trip. The loose edges or the glue strips also interfere with the printing space on a single side of the envelope.
What is needed is an envelope which is reusable and produced from a single unitary material blank and is durable enough to be sent through the mail twice. What is also needed is an envelope which is compatible with existing automated processing machines. What is further needed is an envelope suitable for printing of sophisticated promotional material thereon without interference from the sealing features of the envelope.